Carcinoma of the prostate is the second most common malignancy in men. One-hundred thousand new cases are estimated for 1989. Once diagnosed, the accurate determination of local extent is essential for treatment planning and determination of prognosis. Renewed interest in nerve sparing techniques for radical prostatectomy, as therapy for intracapsular disease have led to the need for improved methods of accurate preoperative tumor staging. Clinical staging methodologies have been unreliable, thus making the development of improved methods for staging a matter of great importance. The objective of this proposal is to employ magnetic resonance techniques to develop improved methods for characterizing and determining local extent of prostate carcinoma through the use of an endorectal surface coil for imaging and spectroscopy. Data obtained from invasive measurements such as histochemical staining and conventional biochemical analysis suggest that the level of citrate is reduced in carcinomas as compared with normal tissue. This reduction in citrate is usually accompanied by an increase in the lipid content of tumor tissue. In benign hyperplasia the citrate levels are found to increase. We propose to employ proton magnetic resonance spectroscopy (MRS) (the STEAM sequence in particular) to monitor these metabolites non-invasively. Our preliminary results indicate that MRS may provide a means to differentiate between BPH and malignancy. The interdisciplinary team includes a urologist, a pathologist, two magnetic resonance spectroscopists, as well as radiologist with expertise in magnetic resonance imaging, genitourinary imaging, and ultrasonography. This proposal includes a detailed study with histopathologic basis of signal intensity variations in magnetic resonance imaging and in transrectal sonography. It will assess the accuracy of magnetic resonance imaging with the endorectal surface coil in defining tumor volume, and evaluating capsular integrity in patients with prostate carcinoma.